| 摘要 |
911,338. Sewing-machines. NECCH1 S.p.A. Oct. 28, 1960 [Dec. 31, 1959], No. 45631/61. Class 112. A sewing-machine, in which the work feed is governed by the angular position of a control member, comprises a first lever detachably connected to the control member and connected at a first point to hand-operated means adapted to rotate the lever about a second and fixed point, and a second lever arranged with one end abutting the first lever when the control member is in the neutral position and adapted, when the control member is in any other position determined by the first lever, to be rotated by hand-operated means so that its other end separates said detachable connection and moves the control member, in opposition to spring means, to a position symmetrical to the neutral position in relation to said other position. The arrangement is incorporated in the zig-zag sewing-machine described in Specification 911,337. A lever 153 is pivoted at 168 within the forked upper end 169 of a lever 170 pivoted on fixed pins 171, 172. The lower end 154 of lever 153 engages a pin 155 on an arm 156 rigid with a rotary pin 157. An arm 158, rigid with pin 157, is connected by a link 159 to an arm 161 rigid with a rotary pin 163. An arm 165, rigid with pin 163, carries a slide 164, the inclination of which determines the rate and direction of work feed. A spring 167 acts on arm 165 to bias pin 155 against end 154 and thereby the rounded upper end 152 of lever 153 against a surface 151 which is held stationary when the automatic feed control of the machine is inoperative. The lower end of lever 170 carries a follower pin engaged with a helical cam surface 174 on a cam disc 175 rigid with a rotary control knob 176. The feed is controlled manually by turning knob 176 to displace pivot 168 and thereby to cause lever 153 to pivot about its upper end 152. A plunger 178, coaxial with knob 176 is pivoted by a pin 181 to the upper end of a lever 180 pivoted on pin 157. In the nofeed setting of knob 176, an extension of pin 181 engages a surface 183 on lever 153 and the lower end 182 of lever 180 engages pin 155. Plunger 178 is then immovable. When knob 176 is turned to a position of forward work feed, surface 183 is separated from pin 181. Plunger 178 may then be moved inwardly till pin 181 again engages surface 183, when the end 182 of lever 180 displaces arm 156, via pin 155, to a position corresponding to a return feed of equal rate. On release of plunger 178 spring 167 reengages pin 155 with the end 154 of lever 153. For automatic control of the work feed, knob 176 is moved to the zero feed position, and a member 141, on which the surface 151 is provided, is arranged to oscillate in correspondence with the profile of a rotary cam 150, when lever 153 oscillates correspondingly about its pivot 168 to vary the feed. Member 141, which is yoke-shaped, is pivoted about a fixed pin 139. A sleeve 140, pivoted and slidable on pin 139 between the arms of member 141, carries on its upper surface an arm 138. A spring mounted within sleeve 140 biases the latter angularly to engage a lug 145 on sleeve 140 with a surface 146 on member 141 opposed to surface 151. Said spring also biases sleeve 140 downwards to engage arm 138 with a lug 137 upstanding from an arm 135 pivoted on a fixed pin 136. A lug 134 depending from arm 135 can engage either a flat surface 132 on a rotary control knob 131, when a lobe 148 on arm 138 engages a fixed abutment 149 to render the surface 151 stationary, or lug 133 can engage a lug 134 upstanding from surface 132 to raise lobe 148 into engagement with the rotary cam 150 for the automatic control of the work feed. |
